Method of installing joint strips in highways



Jan, I3, 1953 c. E. ULRICH METHOD OF INSTALLING JOINT STRIPS IN HIGHWAYS Filed Sept. 8, 1945 Patented Jan. 13, 1953 OFFICE METHOD F INSTALLING JOINT STRIPS IN HIGHWAYS Carl E. Ulrich, Chicago, Ill.

Application September 8, 1945, Serial No. 615,216

1 claim. 1

This invention relates to the construction art and particularly to the art of highway construction.

In highway construction it has heretofore been the custom to rst prepare the sub-grade and to then pave above this grade with concrete. In preparing this concrete paving it has been usual'to pour the concrete in sections of from sixty to' one hundred and twenty feet in length with gaps between the sections. I-Ieretofore it has been the general custom to ll these gaps with a ller strip or a deposit of ller material which would yield under the compressional strain imposed thereon by the expansion of the sections due to increase in temperature.

In these concrete sections, especially in the longer ones, there always develop what are known as planes of weakness, i. e. points at which cracking of the concrete is apt to occur. To localize this condition very thin strips of filler material known as dummy joints are interposed across the sections at short intervals between the main gaps. These dummy joint strips are very thin and are ordinarily projected only part way through the thickness of the section.

There has developed a modern theory that the vrelatively wide gaps between the sections may be done away with and that in lieu thereof the dummy type ller strips may be installed cornpletely through the width of the concrete paving at frequent intervals thus serving the purpose of both plane of weakness fillers as well as c-cmpensating for the expansion and contraction of the concrete. To do this would have many advantages since it has always been a problem to properly seal the wider gaps against the entry of Water and debris which tends to reduce the efficiency of the gap lling material. The relatively thinner strips would largely overcome this diiiiculty and better compensate for both expansion and contraction of the concrete.

However, the substitution of one type of construction for the other poses certain problems. The principal one of these is to provide such a relatively thin but wide ller strip which may be economically manufactured, stand up without breaking during shipping and handling and one which will adequately seal itself to the adjacent concrete structure in order to hold the strip in place and prevent any material ingress of water.

It is the primary object of my invention to produce a ller strip for use at such short intervals in the paving and which will provide the advantages thereof and avoid the disadvantages.

A further object of the invention is to produce a simple and inexpensive device and yet one which will be exceedingly eiective for the purpose Vfor which it is designed.

These objects are accomplished by means of such structure and relative arrangement of parts as will fully appear by a perusal of the following specication and claim.

In the drawings similar characters of reference indicate corresponding parts in the several views:

Figure 1 is a cross sectional view of a highway section showing my improved strip in place.

Figure 2 is a top plan view of a highway showing my improved strip therein and in which the latter is partly in section to show my electrical heat generating means employed in its installation.

Figure 3 is a cross sectional view of the strip itself.

Figure 4 is a perspective view of a short section of a modied form of strip center plate.

Figure 5 is a sectional view of a modied form of strip which employs the plate shown in Figure 4 and as it appears before the application of heat thereto.

Figure 6 is a view as in Figure 5 but showing the strip as it appears after the application of heat thereto.

In its broad aspect my improved strip consists essentially of a metal strip of very thin gauge,

say approximately 11g thick and of arbitrarywidth determined by the use to which it is to be put, and of a length to extend across the width of the pavement, say I0' to I2 as is usual.

This strip I is coated as at 2, to a thickness of from M3" to 1A, with a thermo-plastic sealing compound, such as the thermo-plastic rubber compounds sold under the trade names Para-Plastic or Seala or other types which may have the same desired characteristics, i. e. having a high melting point, well above normal atmospheric temperatures so that they will not run during the highest summer temperatures, and will not become brittle at freezing temperatures. They are, furthermore, capable of being compressed and will, when released, recover Well up to their original thickness. The material. when melted, will adhere to concrete.

In applying these strips to the highway construction they are rst placed in situ above the sub-grade at the desired selected intervals along the highway.

The concrete 3 is then poured along the length of the highway as usual and during this process it ows about and encloses the strips as shown in Figure 1. The concrete is then allowed to cure.

When such concrete is cured and dried heat is then applied to the strips by any means or by any method found practicable. In the present instance I show the use of a motor generator 4 connected by wiring 5 to a piercing contact point 6 driven into the strip l by means of which an electric current can be discharged into the strip to heat the same.

If a single-wire circuit to the strip I from the generator is used, as here shown. the strip insulated by its coating 2 is of course suitablygrounded at the end opposite the point of contact of element 6 with said strip, as indicated.

The strip, which forms a resistance element, is then heated up to or beyond the melting point of the coating 2. Such coating, previously smooth, then melts and flows andy oozes into the rough surface and interstices of the adjacent concrete slab. When allowed to cool it is then interlocked and adhered firmly to such concrete. Because of its compressible and flexible characteristics it will thereafter follow the concreteduring periods of expansion and contraction under changing temperatures. Since it isthoroughly interlocked to the concrete it will Vform a perfect seal against water entering to the subgrade through the gap, or from the sub-.grade into the gap.

While I have shown the strip as for use as a joint filler which extends completely through the thickness of the concrete it will be obvious that it may be made narrower to serve either as a dummy joint or as a seal below Ythe regular dummy joint now commonly employed.

Also in practice instead of using the plate Igas the center element, other substitute materials such as wires or the like might be used just so long as they were relatively stii and of heat conductive material.

In Figures 4 `to v6 inclusive I show a modified form of center plate. Here the center plate is shown in the form of a V-shaped 'spring metal member 'I having its upper edges initially pressed and held together under tension by meltable solder buttons 8 and the plates 'being covered with the sealing compound as in the other species.

When this modified form is placed in the highway and heated such heat will not only cause the flow of the-compound as above described but will also melt; the Vsolder buttons. rI'hiswill then allow the tensioned sides of the V-member to spring open as lshown in Figure 6 and thus Aadd greater resiliency to the strip while maintaining all the advantages of the sealing compound as above described.

If desired the hollow space in the strip as shown in Figure 4 may be filled with an asphaltic or like compressible compound in order to keep out water and dirt.

It will be obvious that my improved strip material as shown in Figure 1 may be made up and packaged in various ways for shipment Nand use but these are not described as they form no essential part of my invention as dened in the appended claim.

Having thus described the invention, the following is.V claimed as new and useful and upon which Letters Patent is desired:

Ihat method of applying in a highway a strip of compressible and expansible material having a melting point above maximum atmospheric temperatures and which strip includes an electrical resistance element, such method consisting inthe steps of placing lthe strip in place, pouring concrete on each side thereof, and, after the concrete has s et and dried, then passing an electric current through the resistance element to a degree sujicient to heat the same at or above the melting point of the meltable material. whereby such material will melt and flow into the interstices of the vertical surfaces o f the adjacent concrete, and then discontinuing the electric current. i' v REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date Re. 17,369 Fischer July 9, 1929 1,216,654 Burke Feb. 16, 1916 '1,484,303 Gundiach Feb. 19', -1924 1,726,215 De Both, Aug. 27, 1929 1,960,120 Mehring May V20', 1934 1,972,439 yDresser Sept. 4, 1934 2,071,299 Gammeter Feb. `16,-'1937 2,148,595 U11-ien Feb. 28', 1939 2,173,622 Crooks et al. v Sept. 19,1939 2,221,431 omansky Nov. v12', A1,940 '2,315,588 vBrickman 7 Apr. 6, 1943 2,319,105 'Billner May 11,1, 194,3 2,354,586 `Fischer July 25, 1944 

